Tables having tops which are vertically and/or pivotally adjustable have proved useful in many applications, particularly in hospitals and similar situations in which it is desirable to have a table which may be used by a person in a bed or a chair.
One type of vertically adjustable table has a base with an upright post and a vertical row of openings in the post. A tubular member which supports the table top is telescopically slidably received over the post and has a lever supported thereon for pivotal movement about a horizontal axis, the lever having a locking pin engageable with the openings in the post. A table of this type is disclosed in U.S. Pat. No. 2,685,487. A problem with this type of arrangement is that the weight of the table top and items thereon is transferred to the lever through the pivotal support and is then transferred through the pin on the lever to the post. This necessitates a pivotal support capable of carrying a significant amount of weight, which support is expensive to manufacture and therefore increases the total cost of the table.
A problem frequently encountered with tables having pivotally adjustable tops is that the mechanism releasably securing the table in a selected pivotal position permits a certain degree of rotational play between the table top and the base structure. Mechanisms capable of significantly reducing this rotational play are known, but typically are expensive to manufacture and thus increase the cost of the table.
It is therefore an object of the present invention to provide an adjustable table having a mechanism of the type described above for releasably locking the table top in a selected vertical position, in which mechanism the pivotal support for the lever does not carry any part of the forces generated by the weight of the table and items placed thereon.
It is a further object of the present invention to provide an adjustable table having a mechanism capable of securely locking the table top in a selected pivotal position with little or no rotational play, which mechanism is relatively inexpensive to manufacture and is easy to operate.
It is a further object of the invention to provide an adjustable table, as aforesaid, which is durable and requires little or no maintenance.